Automatic telephone system.



G. A. YANOCHGWSKI a. H. E. HERSHEY.

Au'rommc TELEPHUNE SYSTEM.

` APPLICATION FILED NOV. 28. 1913. "X u 1,216,534, `utentd Bel). 20,1917.

2 SHEETS-SHEET` 1.

G. A. YANCHOWSKI (IL E. HEFSHEY.

AUTOMATIC, TELEPHONE SYSTEN.

APPLICATION FILED NOV. 28, 1913.

Patented Feb.20,1917.

wy QM@ www @JM N L Y i M@ @W MH UNITED STATES PATENT OFFICE.

GEORGE A.`YANOCHOWsKI, OF CHICAGO, ILLINOIS, AND HA aRY E. HERSHEY, OF cWHITEWATER, KANSAS, AssIGNOEs To AUTOMATIC ELnCTRIC COMPANY, o1 CHICAGO,ILLINOIS, A CORPORATION OF ILLINOIS,

AUTOMATIC TELEPHONE SYSTEM.

Application led November 28, 1913.

. Zeus of the United States of America, :ind

residents of Chicago, Cook county, Illinois,

Aand Whitewater,` Butler county,.Kansas, re-

spectively, have invented certainnew and useful Improvements inAutomatic Telephone Systems, of which the following is a specification.

()ur invention relates to improvements in automatic telephone systems,and has for its object the provision of means for auto maticall yswitching a connection to an operator in case any one of the switchesemployed in establishing the connection lands on a trunk which is out oforder.

In the accompanying drawings we have illustrated our invention inconnection with an automatic telephone system employing 'line switches,selectors, repeaters and connectors ot' well-known types, and have shownh'ow the connection will be automatically switched to an" operatorsposition, first, if the selector strikes a trunk which is open betweenthe selector and the repeater;

` second, it the trunk is open between the rei `cases not `only wherethe` subscriber-s line has become accidentally open, but also 1n` peaterand the next succeeding switch; and, third, il thc connector lands on anopen, line. This last feature 1s particularly useful 1n cases where asubstation has been disconnected. Heretofore, in such cases,it has beencustomary to provide special means for switching the connection fromVsuch a disconnected line to an operators board in order that the ope'ator can inform the calling subscriber that the telephone of thedesired called subscriber has been disconnected. By our invention,however, such switching o't' the connection is accomplishedautomatically.

Referring to the drawings, Figures 1. and 2 show a complete` connectionbetween a. calling substation A and a called substation A inra systemembodying the principles ot' our invention. i

Fig. 3 is a modified arrange-mcnt'of a portion of the circuits.

The substation A and the apparatus shown in Fig. 1. are assumed to belocated in. a branch exchange, while the apparatus Specication ofLetters Patent.

Patented Feb. 20, 1917.

Serial No. 803,4 26.

shown in Fig. 2 is assumed to belong to the l main exchange. rIheconnection shown is extended through tl e subscribers individual VswitchC and the selector E at the branch exchange and through the repeater F,which latter 1s lncluded 1.1.' atrunk line leading to the man1 exchange`f1'om.whence the connection extends thr )ugh the connector H to thecalled substation. The selector E in the branch exchajng e, besideshaving access to trunk lines leading to the main exchange, is also'assumed to lave access to connectors in its own exchange for thepurpose of corupleting connection i' Yith the branch exchangesubscribers. It will be -clearly understood by those versed ir the artthat so-called selector switches n' ay be inserted between the mainoilice terminal of the trunk line and the connector l-I, thesaidselectors to be similar to the olie shown at E. At I is shown anoperatois set, together with a lamp associated Wit l1 a key, the samebeing assumed to ,be mounted on a complaint or trouble desk. y

yT he substation A shown herein may be of any suitable or appl oved typeand comprises the usual receiver l, transmitter 3, ringer 4 andcondenser 5. Being an automatic substation itis also p1 ovided with animpulse transmitter or ealliiig device, which is represented herein by apair of impulse springs (i and T and an impl lse wheel 8, which latteris assumed to be controlled through the` medium ot' a fingei hole* dia](not shown) in such a manner trat the impulse springs (i and 7 may bei'iomenta'rily separated af number of times corresponding to each digitof the number to bt called.

The subscriber-s individual switch C is of the general typ: ofsubscriliers switch shown in British pa 'Lent to R. W. James No. 26,301of 1906, beiI g, however, of the particular type disclosed in Britishpatent to T. G. Martin No. 1419 of 1910. This line switch comprises,umong other details, a plunger not shown) attached to the end of aso-called plunger arm 24. which is controlled by the magjnet 150. Themagnet 159 comprises four I rindingns, i'iamcly. a pulldown Winding 19,a cuto` or holding winding 27, a line winding 1l and an auxiliary 8 idleswitches in position to engage the terthe windings 19 andv 27 isseparate from that of the windings 11 and 20. The windinv 19 operatesboth the plungeriarm 24 and the armature 25, while the winding 27 set ofsprings is shown, each line switch is provided with a plurality of suchsets, each set forming the terminal of atrunk line leading to a firstselector switch E. Each trunk line is connected in multiplel with :'hecorresponding springs of all the line switches of the group which iscontrolled by the master switch D. The switch C is 'controlled by thesubscriber through the medium of the line winding 11, as willhereinafter be more fully explained.

Themaster switch D is of the same general type as that disclosed inBritish Patent No. 26,301 0151906, referred to above, being, however, ofthe particular type disclosed in lsaid British Patent No. 1419 of 1910.The

function of the master switch, as is well known, is to maintain theplungers of all minal of an idle trunk line.

The first selector switch E is of the general type of selector switchdisclosed in United States Letters Patent No. 815,321, granted March 13,1906, to Keith, Erickson and Erickson, except that the circuits aremodified to adapt the `switch to operate in a system in whlch it iscontrolled by impulses delivered over two sides of the line in sries.Among other details, the selector E comprises a bank of contactsarranged in horizontal rows or levels, which contacts are adapted to beengaged by a set of wipers 63, 59 and 64 carried upon a shaft (notshown) which has a vertical movement controlled by the vertical magnet50 and a rotary movement controlled by the rotary magnet 55. Theoperations of the various parts of the switch are controlled through themedium of the double-wound line relay 32. The usual side switchcomprising the wipers 51 and 60 is controlled by the private magnet 54in the usual and well-known manner. Means for permitting the switch tobe restored to normal position are provided in the release magnet 143,which, upon energizing, withdraws the retaining pawls from the shaft.The springs 52 close only when the switch shaft has been raised one ormore steps from its lowest position. The

relays 40 andA 49 are slow actingthat is,

they denergize slowly after their energizing circuits are broken.

The repeater F'comprises a combination of relays which are for thepurpose of receiving impulses from the calling substation and repeatingthenrover the trunk conductors 84 and 86 to the connector Hin the mainexchange. These relays are controlled directly by means of thedolible-wound line relay 65. The relays 74, 85 and 96 are slowactingthat is, they denergize slowly after theirenergizing circuits arebroken.

The connector switch H is of the same general type ot' connector switchas that disclosed in United States Letters Patent No. 815,176, grantedMarch 13, 1906, to Keith, Erickson and Erickson, the circuits, however,being modified to adapt the switch to Operate ina system in which thecentral oiice apparatus is controlled by impulses delivered over twosides of the line in series. Like the selector the connector is providedwith a shaft (not shown) carrying the Vline relay 81 is connected withthe line through the reversing springs of a so-called back-bridge relay134, through the winding of which latter relay the called line is pro-,vided with talking current. The ringing relay 125 is the means throughwhich ringing currentl is applied to the called line.

At Q is shown a busy signaling machine which provides a busy signal,said busy signal being applied to the calling line through the .mediumof the busy relay 145 in case the called line is in use. The substationshown at A and the line switch C are similarl in all respects to thesubstation A and the line switch C.

For the purpose of supplying battery current for operating the apparatusat different exchanges and for talking purposes, there are shownthroughout the drawings -batteries B and B having one terminal groundedat G and G. At R is shown a ringing current generator for supplyingringing current to the called line.

A general description of the apparatus having been given, it will now beexplained how a connectionis extended from a calling substation A to acalled substation A. We will assume the number of the substation A to be222. Since the automatic switching apparatus disclosed herein is ingeneral well known in the art and is described in the publicationsherein referred to, its operation will be explained in a more or lessgeneral manner.

Upon the removal of .the receiver from the switch-hook at the substationA preparatory to making a call, an energizing circuit is is thereuponenergized. The calling sub scriber now operates his calling device forVthe first digit 2 of the called number, whereby the substation impulsesprings 6 and 7 are operated twice momentarily, each time breaking thecircuit of the selector line relay 32. The relay of theselector beingslow acting does not denergizey during the momentary interruptions ofits circuit by the lline relay 32 and consequently, each time the latterrelay denergizes, an impulse is transmitted over the circuit extendingfrom ground G3 through the springs 38 and 48, springs and 46, relay 49,vertical magnet and the side switc wiper 51 (in first position) tobattery B. hevrtical magnet receives two impulses over the circuit and.operates to raise the switchshaft and wipers two steps to a positionopposite the second row or level of bank contacts. The off-normalsprings 52-close as soon as the shaft is raised one step, but thecircuit of the release magnet 143 still remains open at the springs 45and 47. The relay 49, which is g included in circuit with the verticallmagnet,

vas

lcv

is energized'by the rst impulse, but being a slow actin relay does notallow its armature to fallv ack until after the last impulse has beendelivered` In its energized position the relay 49 closes a circuit fromground G through the springs 53 and th/e private ma net 54 to battery B.This circuit is broen when the relay 49 denergizes after the lastimpulse has been delivered to the vertical magnet, the breaking of saidcircuit causing the private magnet 54 to dee'nergize, thus permitting.the side switch to pass to second position.

In passing from first to second position the side switch wiper `51disconnects the battery from the vertical magnet 50 and closes a circuitthrough the rotary magnet 55. The circuit extends from ground G' throughthe interrupter springs 56, rotary magnet 55 and the side switch wiper51 (in second position) to battery B. The rotary magnet 55 will thencontinue to operate in a manner `similar to that of a buzzer' to rotatethe wipers step by step as long as the side switch remains in secondposition. As soon as the rotary magnet energizes the first time, acircuit is closed from ground G6 through the contact point 57, armature58 and the .private magnet 54 to battery B. The private magnet 54isenergized over this circuit and is again denergized when the rotarymagnet 55 denergizes after having rotated the wipers the first stepprovided the first trunk line upon whic 1 the Selector wipers arerotated is idle. It the trunk is busy, however, the private wiper 59finds the contact which it engages proveded with a guarding groundpotential. A new circuit is then closed through the private magnet 54extending from said grounded contact through the wiper 59, side switchwiper (S0 (in second position) and the private magnet 54 to battery B.Ther( fore the private magnet 54 does not dener gize when the rotarymagnet armature falls back and the side switch is locked in seconlposition. The rotary magnet 55 then continues to advance the wipers stepby step until the contacts of an idle trunk are reached, whereupon theprivate magnet denel gizes, permitting the side switch to pass to thirdposition and thus break the circl it of the rotary magnet 55. When theside :avitch wiper 51 reaches third position, a circ lit is closed fromground Gf through the sp1 `ings 41, springs 61 of the relay 62, relay 35and the side switch wiper 5l (in third position) to battery B. It willbe seen that tlie relay 62 will not be euer gized at this th 1e onaccount oi being shunted by ground 3*.' The relay 35, upon energizing,operates to disconnect the line relay 32 from the` line and extend theconnection through the wipers 63 and`64 to the repeater F. When thecircuit is thus extended to the 'epeater, the line relay` G5 isenergized ovel a circuit extending from ground G7 thro ugh the lowerwinding of the line relay 65, springs 66 and G7, wiper (i4, springs 68anc 34, springs 31 and 30, line conductor 15 to and through thesubstation A,-line conductor 16, springs 28 and 29,

71 and the upper winding of the line rel-.1y to battery B. The linerelay 65, upon energizing, clones a circuit from ground G" through thesp' 'ings 72 and 73 and the relay 74 to battery l5. The rela-y 74, uponenergizing, provides a new circuit for the relay 35 of the selector Eand the cut-off winding 27 of the line switch C for maintaining therelay 35 and the cut-off coil 27 energized after their original circuitis broken by the denergization of the slow acting relay 40. 'l'hiscircuit extends from ground G through the s1'. rings 75 and 7G, contact78, wiper 59 and he side switch wiper 60 (in third position), at whichpoint the circuit divides, one I: art continuing through the springs 61of the relay 62 and the relay 35 topbattcry B. The other -branch extendsfrom the side switch wiper 6() (in third position) through the springs42 and 43 and the cut-off coi 27 of the line switch (l to battery B. Tiecircuit also divides at the spring 43 and the conductor 44 connectsground to the connector private bank contacts which a:e associated withthe line springs 36 and (39, wiper b63, springs 70 and switch C. A Therelay 62 does not pull up at this time due to the fact that it isshunted out by ground G9.' The trunk leading to the repeater F is alsoprotected from seizure over any of its multiple contacts by a guardingpotential extending from ground G9 to the private bank contact 78 andthe multiples'thereof. Another result of the energization of the relay74 is the closure of -a circuit from ground Gl through the springs 75and 77 and the left-hand winding of the relay 79 to battery B. Therelay79 is so constructed and adjusted that it cannot be operativelyenergized by one winding alone, but requires the combined energizationof both its windings to cause it to attract its armature. The engagementof the springs 80, upon the energization of the repeater Iline relay 65,closes a circuit, through the line relay 81 of the connector H, saidcircuit extending from ground G1 through the lower winding of the relay81, springs 82 and 83, over the trunk conductor 81, through the springs80, relay, 85, righthand winding of the relay 79, trunk conductor 86,springs 8,7 and 88 and the upper winding of the line relay 81 to batteryB. Although both windings of the relay 79 of the repeater now carrycurrent, the relay is not operated because the current flows through thetwo windings'in opposite directions. It will be seen that theenergization of the relay 85 causes the springs 8 9 to be separated,thus keeping the circuit of the relay 90,0pen. The energization of theline relay 81 of the connector serves to close a circuit through theslow acting relay v91. This circuit extends from ground G11 through thesprings 92 and 93 and the relay 91 to battery B.

The apparatus is now in position for the reception of impulses for thesecond digit 2. The line relay 65 of the repeater F is denergized twiceby the impulses for this digit, each time breaking the circuit of theconnector line relay 81 at the springs 80. The relay 74 of the repeaterbeing slow acting does not denergize between impulses. Consequently,each time the line relay 65 deenergizes it also c loses a circuit fromground GB through the springs 72 and 94, springs 95 and the relay 96 tobattery B. The relay 96 iS energized by the first impulse and remains inits energized position until after the last impulse has been delivered.In its energized position the relay 96 disconnects the condensers 97 and98 from fthe trunk lines 86 and 84 and short-circuits the right-handwinding of the relay 79 and the relay 85 and thus removes theirresistance from the cir.- cuit of the connector line relay 81 while itis operating. The relay 96, upon energizing, also opens the springs 99to prevent the circuit of the relay v90 from being closed when.

the relay 85 denergizes, due to being shortingiof its circuit by theline relay of the repeater, a circuit is closed from ground G11 throughthe springs 92 and 104, springs 105 and 106 (the slow acting relay 91remaining energized between impulses), relay 107, vertical magnet 108and the side switch wi r 109 (in first position) to battery B. hevertical magnet 108 is energized twice over this circuit and operates toraise the shaft wipe-rs two steps. The slow acting relay 107 isenergized in series with the vertical magnet'108 and does not denergizeuntil after the last impulse is delivered. Upon energizing, the relay107 closes a `circuit from ground G12 through the springs 110 and 111and the privateJ magnet 112 to battery B. When this circuit is brokenafter the last vertical impulse has been delivered to the verticalmagnet 108, the private ma'gnet 112 denergizes and the side switchpasses to second position. By this action the side switch wiper 109transfers the battery connection from the vertical magnet 108 to the.rotary magnet 113. When the calling device 4 is operated for the lastdigit, the repeater I4` operates inthe same manner as for the previousdigit. Each time'the connector line relay 81 denergizes in response tothe impulses, a circuit is closed from ground G1' through the springs 92and 104, springs 105 and 106, relay 107, springs 114, rotary magnet 113and the sideswitch wiper 109 (in second position) to battery B. Therotary magnet 113 is energized twice over this circuit and operates torotate the wipers onto the contacts of the desired line. The relay 107operates in the same manner asfor the previous digit to close thecircuit of 'the private magnet 112, while the rotary magnet isoperating. If the called line yis idle, the private magnet 112denergizes when its circuit is broken by the relay 107 after the lastimpulse is delivered to they rotary magnet- 113 and the side switchpasses to third position, completing the connection with the called linethrough the side switch wipers 11.) and 116,--shaft wipers 117,and 118and conductors 119 and 120. The movement of the side switch wiper 121 tothird position provides a guarding potential` for the conconnector ilisreversed in direction.

. this circuit includes the interrupter 124, the

relay 125, is energized intermittently, cach time operating to close asignaling circuit from one terminal of the generator R through thesprings 126 and 127, line wiper 117, conductor 119, springs 128, lineconductor 16', condenser 5', ringer 4', line con- `ductor 15', conductor120, line wiper ,118.v

springs 129 and 130 and the relay 131 to the other side of thegenerator. ln addition to ringing the bell at thel substation A', thegenerator current also energizes the relay 131, causing it to separatethe springs 132 andthus keeping the circuit of the relay 1553 open` Thepurpose of this relay 133 will be hereinafter more fully described. Therelay 133 is made slow acting, e., slow to deenergize after its circuitis broken, and likewise slow to energize upon its circuit being iliade,so that it will not energize duringl the instant between the time thatground (1 is placed upon its circuit by the interrupter 124 and the timethat its circuit is broken by the springs of the relay 131, due to the4generator current being projected on the line. Then the calledsubscriber removes his receiver, the calling substation is provided withtalking current through the windings of the back-bridge relay 134, whichrelay, upon energizing. closes the circuit of the ringing cut-oil' relay167, said circuit extending from ground (im through the side. switchwiper 121 (in-third position), springs 136 and the relay 167 to batteryB'. The relay 167, upon energizing. interrupts the cir cuit of theringing relay 125 at the springs 133i and closes a locking circuit foritself through its own springs independent of the springs 136 of theback-bridge relay 134. lt may be mentioned here that in addition to theabove. the relay 167 also opens the springs 1,37, thus permanentlyopening the. circuit of the relay 1253. further result of theenergization of the back-bridge relay 134 upon the response o1 thecalled subscriber is the shifting ol' the springs 13H and 139, whichtransposes the connections between the. windings oi the relay Sl. andthe trunk conductors S4 and H6. whereby the ciirrent in the' trunkbetween lhe repeater l*` and the rlhis reversal of the current causesthe two windings ol the relay 71) of the repeater F to assist eachother, whereby the relay itselfjs energized and in turn operated toreverse the direction of the current to the calling substation.

After the con versation is completed, the connection is released by thehanging up of the receiver at toe calling substation in the t'ollouiingrmaniu r: lVhen the receiverat the substation A is --estored to theswitch-hook, the separation ot' the .hook-switch springs destroys theenergizing circuit of the repeater line relay 65, which, upondenergizing, breaks the circuit of the relay S1. The linel relay 81 of111e connector, upon denergizing, breaks the circuit of the relay 91,which in turn dei nergizes and closes the circuit of the release magnet140. This circuit extends from ground (in through the springs 92 and104, spi-ir gs 105 and 141, off-normal springs 142 and :he releasedmagnet 140 to battery B'. The release magnet 140, upon energizing,oper.l tes to release the connector` whereupoi its own circuit is brokenat the. onorm il springs 142 when the in the line leading switchshaftreach its lowest position. The

relay 85 of the reneater F being slow acting will not deinergizcimmediately upon its circuit being broken at the springs S0. but willremain energized a length of time `sutlicient for the rela] 74 todenergize and remove ground 'from the spring 76, so that when the relaySa does deiinergize, allowing' the springs 89 to rome into contact, thecircuit of the relay 9h will be open at the s ring 76. When the relay 74of the repeater 1% deenergizes it brealls the circuit of the relay35,01: the. selector E and also of the cut-oil' winding of the. line.switch C. A circuit is now formed from ground G through the relay 62 andthe n klay 35 to battery B. The` resistance of the relays is such thatthe relay 62 becomes energized, but the relay 35 deinergizes` closingthe circuit of the release magnet 143 from grouml G through the springs38 and 48. springs 45 and. 47, springs 144. olf-normal sltrings 52 andthe release magnet 143 to battery B. The release magnet 143. uponenergizing, operates to release the selector. wherfnpon its own circuitis' broken at the oil'- normal springs when the switch shaft r1 achesitslowest position. .\t the same time a circuit is formed from grouiid(}"".throug i the relay 62, springs 61, springs 42 and 43 unlthecut-off`coil 27 to battery l, rlhe iesistance. of the coils is suchthat the cu-oti` `coil 27 deiinergizes, thereby allowing tie plunger arm24 to return to normal. lt will be seen'that as Soon as theswtches and1C are released by their release. magnets 2i and 143 the circuit 0f therelay 62 is also opened and the said relay in turn deenergizes. i

lf, when the connector switch Wi rs come in contact witi the calledline, this line is busy. then there will be'the usual guardlingpotentional upon the connector private' bank contact,A Upcn lthe privatewiper en.-

ies

' lay 40 and then, after gagi-ng this guarding potential, a busy signalwill be. sent back to the calling subscriber from the busy machine Q inthe well-known manner. The calling subscriber, upon receiving the busysignal, hangs the receiver upon the hook, thereby releasing theconnection in themanner above described.

A general description of the operation of the system having been given,the feature of our invention will now be explained whereby, should a'subscriber -in making a call meet with aftrunk or line which is out ofqrder, the'. said subscriber will be automatically connected with atrouble or com-y plaint operator.

The first case to be considered is that in which the shaft wipers of theselector E come to rest upon a set of contacts having an opening ineither the positive trunk, the negative trunk, the release trunk orcombinations .of the same. Under any of the above conditions theconnection from ground G" in the repeater F to the private wiper 59 willbe broken. If the release trunk itself is broken, this, of course,breaks this ground connection, while if either the positive or negativetrunk is broken, the circuit` or' the. line relay 65 of the repeaterwill bc broken and the relay 71 will not be energized to connect groundG to the private wiper 5f). As before pointed out, the relay 62 is firstshort-circuited through the ground connection (l controlled by thereconnection is established with the repeater. this relay 62 isshort-circlntcd by the ground connection through the prlvate wiper 59.Therefore,

when there is no such ground on the private wiper 5S), due to thc trunkbeing open, then as soon as the relay l() falls back, in the. mannerpreviously described, ground is removed froni the spring 41, the relay62 will no longer be shunted out and a. circuit will be closed fromground G15 through the relay 62. relay 35 and the side switch wiper 51to battery l. The' resistance of the relays is such that the relay 62energizes, while the relay 35 deinergizes. The energization. of therelav 62 closes a circuit from ground Gf'through the springs' 152. lamp15+ and the springs 153 to battery `B. The dcncr` gizat'ion of the relay35 again connects the liuc relay 32 with theV substation A, which relay32 therefore cnergizes and again closes the circuit ot' the relay 40,whereby ground is again placed upon the spring 41. thus affording a.holding circuit for the cut-off coil 27 of the line switch C. Theplunger of the line switch (l is not withdrawn from the bank springsduring the period of time that ground G* is broken for the followingreason: W'hen ground (l is removed, a second holding ground for thecut-oli coil 27 of the line Switch C is provided from ground G15 throughthe relay 62, springs 61, springs 42 and '43 and the cut-off' coil 27 tobattery B. However, when the relay 62 energizes, the springs 61 areseparated, leaving the cut-off coil 27 without a holding ground. Thecut-ofi coil 27 therefore denergizes, but the. armature 25 being a lightarmature and carrying heavy spring tension falls back before the plungerarm 21 has overcome its inertia. The arma,- ture 25, upon falling back`again places the line relay 11 in the circuit of the substation A. Thereceiver at the substation A being removed at this time causes a flow ofcurrent through the line relay 11. This line relayll, upon pulling up,closes a eircuit through the pull-in winding 19,'which attracts thearmature 25, again breaking the circuit of the line relay 11. Thisbuzzing action will keep up. without the plunger being removed from the.bank` until the ground is again connected from G* to again energize thecut-oil'l winding 27,`which then holds the armature 25 in an operatedposition.4 The ground G* atthis time does not afi'ord a holding circuitfor therelay 35 on account of the springs 61 being opened by the relay62. The complaint operator, upon seeing the lamp 154 lighted, throws thekey 156 to the right, thereby opening the circuit. of the lamp ll andbridging the secondary other induction coil in series with her receiveracross the line conductors of the selector E. The operator can nowconverse with the subscriber at the substa` tion A and inform him thatthe trunk is out of order. Also., it will readily be seen that. shouldthe subscriber hang up his receiver, the selector E will not be releasedon account of the secondary winding of the operator`s induction coilbeing bridged across the line conductors of the selector E until the key156 is restored. This is of value in that the operator can hold theconnection up until the attendant at the automatic exchange has locatedthe trunk which is in trouble.

A modified arrangement for obtaining the above result is shown in Fig.3, in which are shown a number of relays which may be embodied in aselector, such as the selector The lsame reference numbers are used inFig. 3 to indicate like parts in Fig.v 1, except that the prime mark isadded in each instance. In this modification a slow acting relay 165 hasbeen added, its circuit being controlled by the springs 166 of the relay35. The conductor from the spring 42" passes through the springs 162 and163 and from thence to the spring 61. When the relay 35 becomesenergized, due to ground from G, vin a manner similar to that describedin connection with Fig. 1. a circuit is closed through the relay 165,which relay, upon energizing` places ground from G" through the springs164 and 162 to the spring 42', which affords a holding circuit for thecut-off winding 27 of the line switch C. The spring 162 of the relay 165is ad'usted to make Contact with thespring 1M efore it breaks contactwith the spring 163. Now

when a holding ground fails to come back from the switch ahead, and whenthe ground is .removedtrom the spring 41', the relay GQ is no longershunted out and the relay 35 falls back and the relay 62 pulls up, asabore explained in connection with Fig. 1. 'llie relay lt'i being slowacting will not denergize immediately upon its` circuit being broken,but will continue to hold the ground-tiJ upon the spring 42' for aniiistant, by which time the line relay 32 will again have becomeenergized and in so'doingr close the circuit ot' the relay Jft), whichwill again place ground t'roni tit' upon the springs -tl' to againatl'ord a holding circuit tor the cut-otl winding :2T ot' the liiieswitch when the relay ltii dciinergizes. ln this way the buzzing actionof the liiie switch in Fig. 'l'is prevented.

Ye will next consider the case in which the selector ll comes to restupon the coi1 tacts of a repeater I" whose trunk to the distantlcxchangeis out ot' order` either by reason of being' short-eiieuited. or thepositive'ti'unk open. or the negative trunk open or the negatire trunkgrounded. or combinations of the above. l'nder any ot' the aboveconditionsl the current from the line relay ot' the switch ahead willl'ail to llow through the trunk conductors. and for this reason therelay S5 will not be energized. 'l`lieretoie, as soon as the relay T-llbecomes energized aiul places gr und upon the spring 76. a circuit willb'e tirnied t'roiii ground ("tlirouglitliesprings Tiandt. springs su ofthe relay S5. springs Si!) of the relay titi and the relay .tl tobattery li. 'l`lie relay J0 will thereupon energize and light a lampassociated with an operatoi"s key. similar to the lamp 154 Aand th'e key151'. in front of the complaint v,operator l. 'l`he operator will tliciithrow ier key' and converse with the subscriber in the manner and withthe results described abo-re.

'l`he third case to he considered is that iii which the slialt wipersot' the connector il come to rest upon a set of contacts having anopening iii the line circuit. l'nder these. conditions` when the ringerrelay 125 enorgizes and connects ringing current to the line. thecircuit ol tlic relay 1251, which is connected in series with ilieringing current, will not lie closed due to the' opening in thc line andtliis relay will accordingly not en- Witli the ringer relay 125 in airenergized position and tlie relay lt'i'i' deener` gized` a circuit istoriiied from ground ti through tlie interrupter 124, springs-.131

to battery B. 'lhe energization of therelay 133 closes i locking circuitfor itself4 from ground (nlls through the springs 157, spi-ings 158,reliy 133 and the side switch wiper 109 (in third position) to batterB'. The energizatioi of the relay 133 will ight a lamp associated withan operators kev,

similar to the li' mp 15S-l and the key 156, in

upon an open l ne causes the calling party i to be autoiiiatiinillyconnected with a complaint operator` who. upon inquiring the numberbeing called. can inform the calling subscriber that that telephone hasbeen reniored.

It will thus he seen that we hare devised a rery ellicieni means forautomatically switching thy.` coilinectioii to an operators board inease iii'y one ot' the switches strikes a trunk line wlicli is open.

\}'liile we liav.` illustrated our inrention in connection with anautomatic telephone system of a well-ki own type employing certainwellknowii forms ot' line switches. selectors. repeaters and ciiincctois. it will` ot' course` be understood that it is equally aswell adapted for iis.l iii connection with other automatic orsenii-autoiiiatic systems in which ditl'creiit types of automaticswitches are employed. a. oininvention is not iii any way liinitcd tothe particular type of switch employed.

'liat we claini as our inreiition is:-

1. ln a telephone system. a calling and a called subscr ber`s liiic. iixans including selector aiid con iector switches for establishingconnection letween said lines, and means for signalingyfi ii operatorit' said selector strikes anl opei trunk, or said connector strikes anopen line.

L. ln a telephone system. a calling and a called subscrbcr`s line. meansincludingr trunk lilies. selictor switches. repeaters and vconnectorst'or establishing connection lie tween said lines` and means t'orsignaling an operator if sa d selector strikes a trunk which is open oieither side ot' said repeatei'` or it said con iectoi strikes ar calledline. which is open.

3. ln a teleplone system. a group of trunk lines. an autonatic switchadapted to connect with any one of said trunks` each o said trunks coiiprising a plurality of conductors. agroi nd normally adapted to beconnected with one ol said conductors when springs 137 of the relaylti', relay 132i and .connectioii is tstablislied with said trunk, meansfor removing said ground iii case any the side switch wiper `1,09 (inthird position) and an is open, an by for signaling of the conductors ofsaid trunk operators position, and means controlled t e removal of saidground said operator.v

In a telephone system, a group of trunk lines, an automatic' switchadapted to connect with anyone of said trunks, each of said position, arelay with said operators position, energizing circuits for said relay,1a short-circuit for said relay includline, an autoadaptd to establishconnection line, an operators position, a relay associated with saidiiosition, means for enei'gizing said relay w en said switch strikes aline which is open, an operators signal controlled by said relay, andmeans by which the operator may then establish connection with saidswitch.

n a telephone system, a line, a switch with said line, means forapplying ringing current to a relay connected in series with saidringing current circuit, an operators position, a relay associated withsaid position, means controlled by said first relay for opening thecircuit of said second relay, means for 'closing the circuit of seidSecond means for establishing a talking circuit connection between twopoints, said circuit into normally detached circuit sections, anautomatic progressively movable. switch for closing one of said sectionswith another, supervisory equipment individual to said switch, a controlcircuit for said equipment, said control circuit controlled in turn overa circuit having,lr a section individual to said last mentioned sectionand which conducts current which does not flow over the talking circuit.

progressively closing one ofsaid vsections with another, supervisoryequipment individual to said switch, a control circuit for saidequipment, auxiliary relay in said last mentioned 'not 9. In a telephonesystem, means for estabconnection dividedA section for controlling saidcont-rol circuit, said relay energized by current which does flow overthe tal ing circuit.

lishinga talking circuit connection between relay controlling saidcontrol circuit, said flow energized by current which does not over thetalking circuit.

10. In a telephone system, means for establishing a talking circuitconnection between two points, said circuit connection divided intonormally detached circuit sections, an automatic switch for closing oneof said sections with another, supervisory equipment individual currentwhich does not flow over the talking circuit, and a circuit forcurrentcontrolled over said lirst mentioned section.

In a telephone system, means for estabconnection between connectiondivided circuit sections,

relay equipment, Said relay controlled in turn by said last mentionedsection and energized by current which does -not How over the talkingcircuit.

12. In a telephone system,means for establishing aI circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an autocontrolling,r said equipment, and anauxiliary relay in said last mentioned section for controlling said'supervisory relay, 'said auxiliary relay energized by current which doesnot flow over the talking circuit.

1 In a autoi'iiatic switch for closing one of said sections withanother, supervisory equipment auxiliary elay individual to said lastmentioned section for controlling said su ervisory relay, saidvauxiliary relay energized by current which ing circuit.

14. In a telephone system, means for estabdoes not flow over the talklishing a talking circuit connection between two points, said circuitconnection divided into normally detached circuit sections, an automaticswitch ior closing one. of said sections with another, supervisoryequipment individual to said switch, a supervisory relay forcontrolling' said equipment. an auxiliary relay in said last mentionedsection for controlling said supervisory relay, said auxiliary relayenergized hy current vwhich does not flow over the talking circuit,` thecircuit for 'said current controlled over said first mentioned Section,

l5. ln a telephone system. means forestallishingr a talkingr circuiti-.onnwftion between twolioints, said circuit connection divided intonormally detached circuit sections, an automatic switch for closing' oneoi' said sections with another` supervisory equipment individual to saidswitch. and a supervisory relay for controllingl said equipment. saidrelay under the control oi' lioth of said sec- `vtions and energized hycurrent which doesl not How over the talk-ine circuit.

lti. ln a telephone s vslem. means for es tahlishine a talkingl circuitconnection hetween two points. said circuit connection divided intonormally detached circuit sections,'an automatic switch Jfor closing oneof said sections with another` srq'iervisory equipment individual tosaid switch` and a supervisory 'relay for controllincy said equip ment,said relay energized hy current which does not How over the taikiuircircuit and under the control of said last mentioned seetion torrendering it inolwrative.

17. In a telephone system, means for tahlishinc,` atalking circuitconnection hetween two points, said circuit connection divided intonormally detached circuit sections, an automatic. switch for closing oneoi` said sections with another. supervisory equipment individual to saidswitch, and a supervisory rela)r tor controlling." said equipment, saidrelay energized hy current which does not fiow over the talking circuitand under the control of said last mentioned sec tion for preventing'the actuation of said suliervisory equipment` 1S. ln a telephone.system, means for estahlishingg,r a talking circuit connection he tweentwo points, said circuit connection divided into normaliy detachedcircuit sections. an automatic switch for closing one ol' said sectionswith another, supervisory equipment individual to said switch, asupervisory relay for controlling said equipment. and an auxiliarylrelay in said last mentioned section for controlling said supervisoryrelay .for preventing the actuation 0f said supervisory equipment1 saidauxiliary relay energized hy current which does not llow over thetalliincr circuit.

lil. ln a telephone system` means for establishing a tilllv'ingv circuitconnection hetween two points, said circuit connection divided intonormally detached circuit sections. an autanatie switch for closing' oneot said sections with another. supervisory equipn'ient ini ividnal tosaid switch, a supervisory relay 1er controlling said equipment, and anauxiliary relay individual to said last mentioned section forcontrolling' said slqiervisory rla \l tor preventing the actuation ofsaid supervisory equipment, said auxiliary relay energized hy currentwhich does not flow over the talking circuit. y

QU. ln a te ephonc systeni, means for estalilishingi a .alkingl circuitconnection helween two p iints, said circuit connection divided intoiormally detached circuit sections. an automatic switch lor closing` oneol said sez-ti( ns with another, supervisory equipment im, ividual tosaid switch, a supcrvisory ielay for controlling said equipment, anauxiliary relay individual to said last mentioned secion for controllingsaid supervisory relay, e nd a circuit for said auxiliary relaycontrolled over said lirst mentioned section for preventing theactuation of said supervisory equipment, the circuit for said auxiliaryrelay heini: energized h v current which does nrt iiow over the talkingcircuit.

2l. In a teephone system, means for establishing a 'zalking circuitconnectitm hetween two p iints, said circuit connection divided :into:iormally detached circuit sections, an autrimatieswitch for closing,rone 0f said sectitns with another, supervisory equipment inlividual tosaid switch, and a supervisor) yrelay for controlling; said equipment,Au]rela energized hy current which does nct liow over the, talkingcircuit and under th,l control of both ot said sections for pre venting'the actuation of said supervisory el piipment.

Q2, ln a telephone system, means for ef tahlishiirc` a alking circuitconnection hetweeu two points` said circuit connection divided intonormally detached circuit sec -tions. an autcnultic switch for closingone oi' said sectitns with another, superuser-y equipment in lividual tosaid switch, and a siqwrvisor) relay for controlling Said equipment,said relay energized hy current which does mt fiow over the talkingcircuit and under the control of said last mentioned section i'orrendering it inoperative for preventing the :ctuution oi saidsupervisoryy equipment. 5'

2f-. ln a telephone system, means for establishing a ialking circuitconnection between two p1 iints, said circuit connection divided intonormally detached circuit sections, an autcmatic switch for closing oneof. said Sectio as with another, supervisory equipment, a ielayindividual to said switch for controlling said equipment, and a. controlcircnit fo r said supervisory relay provided with currcnt that does notHow over the talking circuit, said control circuit under the control oi"said last mentioned section.

24. In a telephone system, means for tablishing a talkingr circuitconnection lictween two points, said circuit connection divided intonormally detached circuit tions, an automatic switch for closing one ofsaid sections with another, supervisory equipment, a relay individiullto said switch for controlling said equipment, a control circuit forsaid relay, and an auxiliary relay in Said last mentioned Section forcontrolling said control circuit. said auxiliary relay energized hycurrent which does not fiow over the talking circuit.

In a telephone system, means for establishing a talking circuitconnection hetw`een two points, said circuit connection 'divided intonormallywdetached circuit sections, an automatic switch for closing oneof said sections with another, supervism-y equipment, a relay individual'to said switch for controlling said equipment, a control circuit forsaid relay, and an auxiliary relay individual to said last n'ientionedsection for controlling said control circuit, said auxiliary relayenergized hy current which does not flow over the talking circuit.

26. In a telephone system, means for establishing a talking circuitconnection between two points, said circuit connection divided intonormally detached circuit sections, an automatic switch for closing oneof said sections with another. supervisory equipment, a relay forcontrolling said equiplnent individual to said switch, a control circuitfor said relay, an auxiliary relay individual to said last mentionedsection for controlling said control circuit, and a circuit for saidauxiliary relay controlled over said first mentioned section, thecircuit tor said auxiliary relay provided with current which doesI notpass over the talking circuit.

27. In a telephone system, means for establishinga talking circuitconnection lietween two points. said circuit connection divided intonormally detached circuit sections, an automatic switch for closing oneof said sections with another,v supervisory equipment, a relay iorcontrolling said equipment individual to said switch, and a controlcircuit for said relay. said circuit under the control ot' both of saidsections and supplied with current which does not flow over the talkingcircuit.

28. In a telephone system, means for cstalilishing a talking circuitconnection hetween two points, said circuit connectiondivided intonormally detached circuit tions, an automatic switch for closing one ofsaid sections with another, supervisory equipment, a relay forcontrolling said equipment individual to said switch, and

a control circuit for said supervisory rclay provided with current whichdoes not flow over theY talking circuit, said control circuit under thecontrol of said last mentioned section for rendering it inoperative.

2S). In a telephone. system, means for establishing a talking circuitconnection between two points, said circuit connection divided intonormally detached conductor sections, an automatic switch for closingone of said sections with another, asupervisory equipment, a circuit foroperating said equipment, a magnet controlled over said last mentionedsection energized by current which docs not fi ow over the talkingcircuit, said supervisory equipment circuit under` the control of saidmagnet whereby if the last mentioned section is in normal condition when`the automatic switch operates said magnet is operated to control thesupervisory equipment to prevent its operation. 30. In a telephonesystem, means for estahlishing a talking circuit connection bctween twopoints, said circuit connection divided into normally detachedconductorsections, an automatic switch for closing one of said sectionswith another, a supervisory equipment, a circuit for operating saidequipment, a magnet controlled over said last mentioned sectionenergized by current which does not flow over the talking circuit, saidsupervisory equipment circuit under the control of said magnet wherebyif the last mentioned Section is in normal condition when the automaticswitch operates said magnet is operated to control the supervisoryequipment to prevent its operation, and whereby if the said lastmentioned sec-,tion is not in normal condition, when the automaticswitch operates, said magnet leaves the supervisory equipment free tooperate., and means for operating the same..

3]. In a telephone system, a calling line, a called line, means forestablishing a talking circuit'connection between thc'two, said meansdivided into normally detached circuit sections, an automatic switch forclosing one of said sections with another, means for operating saidswitch, a supervisory circuit associated with said first mentionedsection, a signal in said circuit and automatic means for operating saidsignal when the said last mentioned section is out of norma-l workingcondition when said switch is operated, said automatic nieans operatedby current that does not flow over thc talking circuit.

552. [n a tele-phone system, a. calling line, a called line, a linkcircuit for establishing a connection Awith the called line, anautomatic switch for extending the connection from thc link to thecircuit beyond, means for operating said switch, a supt'aw'isory circuitassociated with said link,- and automatic means for connecting said linkto Said su- A under the control of said other section` 34,. In atelephone system, means for establishing a circuit connection -hetwceutwo points, said circuit connection divided into normally detachedcircuit sections. an automatic switch for closing one ot said sectionswith another, supervisory equipment individual to said switch, a controlcircuit for said equipment, said control circuit under the control ofsaid last mentioned section,

lrelease cquipn'ient for said automatic switch, .and a release circuitfor said switch, said supervisory equipment controlled over said releasecircuit.

In a telephone system, means for cstablishing a circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an antomatic switch for closing one of saidsections with another, supervisory equipment individual to said switch,a. control circuit for said.,eqi,iipineiit, and an auxiliary relay insaid last mentioned section for controlling said control circuit,release equipment for said automatic switch, and a release circuit forsaid switch, said supervisory equipment controlled over said releasecircuit,

36. In a telephone system, means for establishing' a circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an auto matic switch for closing one of saidsections with another, suliervisory equipment individual to said switch,a control circuit for said equipment, an auxiliary relay individual tosaidv last mentioned section for controlling said control circuit,release equipment for said automatic switch, and a release circuit forsaid switch, said super- .yisdiry equipment controlled over said releasecircuit.

37. In a telephone system. means for l talilisliingg; a circuitconnection lictwcen two points, said circuit connection divided intovnormally detached circuit sections` an alito-- iiiaticswitch forclosing' oneot' said sections with another. supervisory equipuientindividual' to said switch, a control circuit for said equipment, anauxiliary relay iii said last mentioned section ior controlling saidcontrol circuit, a circuit for said auxiliary relay controlled over saidone section, release equipment for said. automatic switch, and a releasecircuit for said switch, said supervisory eqnipinail controlled oversaid rclease circuit.

ISS. ln a teli phone system, means for estalilisliinn a ci lcuitconnection lietween two points. said ii-cuit connection divided intonormally deiacheifl circuit sections, an auto matic sa ilch i'i rclosing one ot' said sections with another. supervisory equipmentindii'idual to said switch, a control circuit for said equipment, saidcircuit under the. control ot lioth oi said sections, release equipmentl'l-il said automatic switch, and a release circuit-ifnsaid switch, saidVsupervisory equipment controlled over said rclease cii cuit.

59. ln a tcleihone system, means for establishing' a ciiciiit connectionbetween two points, said ciicuit connection divided into normally detacied circuit sections, an alitoniatii: switch fo r closing one of saidsections with another. iupervisory equipment individual to said switch,a control circuit for said equipment, said control circuit under theconti-ol of s:.id last mentioned section for rendering,r it iniperative,` release equipment for said autom: tic switch, cuit for saidsu itch, said supervisoryequipment controlled over said release circuit.

40. In a teleihone system, means for estalilishiingr a cii mitconnection between two points,`said ciriiit connection divided intonormally detached circuit sections, an automatic switch to closing oneof said sections with another, supervisory equipment ndividiial to saidsi ritcli, a supervisory relay for controlling said equipment, saidrela;1 under the control otl 'aid last nicntioncd section, releaseeqiiipine it t'or said automatic switch, and a, release iircuit lioisaid switch. said supervisory equipment controlled over said releasecircuit.

41. In a telephone system. ineansior cstalilisliing; a cir-uilconnection lietwcen two points. said ciri uit connection divided intonormally delacl ed circuit sections. an alitoiiiatic switch toi closingLone olA said sections with another. ipervisory equipment individual tosaid switch, a supervisory relay for controlling iaid equipment, anauxiliary relay in said ast mentioned sect-ion for controlling' saidsupervisory relay, release equipment for s iid ,automatic switch, and a`release circuit iur said switch, said si|pc.r visory equipmentcontrolled oi'er said release. circuit.

42. .ln a telephone system, means foi'estalilisliinj; a cir( uitconnection between two points, said circuit connection divided intonormally detacliid circuit sections, an aiitomatic switch for closingone ot' said sections with another, sipcrvisory equii'inicnt individualto said switch, a supervisory relay and a release cirfor controllingsaid equipment, an auxiliary relay individual to said last mentionedsection for controlling said supervisory relay, release eequipment forsaid automatic switch, and a. release circuit for said switch, :aidsupervisory equipment controlled over said release circuit.

43. In a telephone systeni. 4means for establishing a circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an uitomatic switch for closing one of saidwith another, su] ervisor v equipment individual to said switch` asupervisory relay `for controlling;r said equipment` an auxiliary relayin Said last mentioned Section for controlling said supervisory relay,a. circuit for Said auxiliary relay controlled over said first mentionedsection` release e uipment for said automatic switch, and a re easecircuit for said switch, said supervisory equipment controlled over saidr alease'circuit.

44. ln a telephone system, means for establishing a circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an automatic switch for closing one of saidSections with another, supervisory equipment individualto said switch, asupervisory relay for controlling said equipment, said relay under thecontrol of both of said sections, release equipment for said automaticswitch, and a release circuit for said switch, said supervisoryeqi'lipment controlled over Said release circuit.

45. ln a telephone system, means for establishing a circuit connectionbetween two point-s, saitircuit connection divided into normallyietached 'circuit sections, an automatic switch for closing one'of saidsections with another, supervisory equipment individual, to said switch,a supervisory relay l'or controllin,f ,1r said equipment, said relayunder the control ot' said last mentioned section for rendering itinoperative, release equipment. torsaid automatic switch, and a releasecircuit for said switch, said supervisor-y equipment controlled oversaid release circuit.

46. l'n a tele'pl'ione system, means for es-V tablishing a circuitconnection between two points, said circuit connection divided intonormally detached circuit sections, an automatic switch for closing oneof said. sections with another, supervisory equipment individual tosaidswitch, a supervisory relay for controlling said equipment, said relayunder the control of said last mentioned section for preventing theactuation of said supervisory equipment, release equipment for saidautor' atic switch, and a release circuit for saidswitch,-saimsupervisory equipment controlled over said release circuit.

47. In a telephone system, means for establishing ai circuit connectionbetween two matic switch for points, said circuit connection dividedinto normali)Y detached circuit sections, an automatic switch forclosing' one ot' said sections with another, supervisory equiljnnentindividual to said switch, a supervisory relay for cosntrollimar saidequipment, au auxiliary relay in said last mentioned section .forcontrolling said sulwrvisory relay for preventing the actuation ot'said. sul'iervisory equipmentlrelease equipment for said automatic Switaand a release circuit for said switch, said supervisory equipmentcontrolled over said release circuit.

48. ln a telephone system, means for eS- tahlishiner a circuitconnection between two points, said circuit connection divided intonor-mall)r detached circuit scctions,'an automatic switch lor closing!one of said sections with another, supervisory equipment individual tosaid switch, a supervisory relay for col'itrolling said equi pn'ient, anauxiliary relay individual to said last mentioned section` forcontrolling said supervisory relay for preventing' the actuation ot'said super visory equipment, release equipment for said automaticswitch, and a release circl'iit for said switch, said supervisoryequipment controlled over said release circuit'.

49. ln a telephone system, means for eS- tblishing acircuit connectionbetween two points, sani-circuit connection divided into normallydetached circuit sections, an automatic switch for closing' one ot'said-sections with another, supervisoryY equipment individual to saidswitch, a supervisory relay for cmitrolling,` said equipment, anauxiliary relay individual to said last mentioned section forcontrolling said supervisory relay, a circuit for said auxiliary relaycontrolled over said first mentioned section for preventing theactuation olf said supervisory equipment, releasc equipment tor said.automatic switch, and a. release circuit for Said switch, saidsupervisoiy equipment controlled over said release circuit.

50. ln a telephone system. means'tor estab# lishing' a circuitconnection het-Ween two points, said circuit connection divided intonormally detached circuit sections, an auto` maticswitch for closing oneot said sections with another` supervisory equipment individual to saidswitch, a. 'supervisory relay for controlling said wluil'nncnt, saidrelay Under the control ot both .of said sections for preventing theactuation oi said supervisory equipment, release equipment for maticswitch, and a release circuit for said switch, said supervisoryequipment controlled over said release circuit.

51. In a telephone system, means for establishing a circuit connectionbetween two points. saidkcircuit connection dii ein into normallydetached circuit. sections, a"n autoclosing one of said sections withanother, supervisory eqiipment indisaid autovldual to said switch, asupervisory relay for controlling said equipment. said relay under thecontrol otE said last mentioned section for rendering it inoimrative forpreventing,r the actuation of said supervisory equii'n'nent, releaseequipment for said automatic, switch. and a release circuit for saidswitch. said supervisory equipment controlled over said releasecilf'cuit.

l'ii a telephone system. means for establishing.P a circuit connectionbetween two points. said circuit connection divided into noruiallydetached circuit sections, an automatic switch l'or closing one of saidsections with another. supervisory equipment, a relay for controlling'said equipment individual to said switch. a control circuit for ,saidrelay. said control circuit under the control of said last mentionedsection. release ei'piipnient for said auton'iatic s..itcb. and arelease circuit for said switch. said suiiervisory equipment controlledover said release circuit. I

5?. Tn a telephone system. means for establishingr a circuit connectionbetween two points. said circuit' connection divided into normallydetached circuit sections. an automatic switch for closin; r one o'fsaid sections with another. supervisory equipment. a relay t'orcontrolling said equipment individual to said switch. a control circuit;for' said relay; au auxiliary relaiT in said last mentioned section forcontrolling said control circuit. release equipment for said automaticswitch. ind a release circuit for said switch. said supervisoryequipment cont'rolled oi'er said release circuit. Y

."i-t. Tn a telephone system. means for.' establishiiuer a circuitconnection between two points. said circuitconnection divided intonormally detached circuit sections. au alitoniatic switch 'for closinglone of said sectiffns with another. suiwrvisory equipment, a relay forcontrollingT said equipment indii'id-iial to said switch. a controlcircuit fol said relay. an auxiliary relay individual to said last'mentioned section for controlling said control circuit. releaseeqliipiiient for .said ,automatic switch. and a release circuit for saidswitch. said supervisory ei'juipinent controlled over said releasecircuit.

ln a telephone system. meansl for establishiiuLV a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections. an automatic switch l'or closing one ol' saidsections with anotliir. supervisory equipment. a relay l'orcontrolling.: said equipment individual to said switch. a controlcircuit' for said relay. an auxiliarv relay individual to said last'mentioned section l'or controllingr said control circuit. a circuit l'orsaid auxiliary relay controlled over said first n'ientionwl section.release equipment for said automatic switch, and a release circuit forsaid switi h, said supervisory equipment controlled over said releasecircuit.

56. ln a ielephone system, means for establishing.,Y a circuitconnection between two points. said iireuit connection divided intonormally detiched circuit sections. an automatic switch lior closingrone of said sections with another supervisory equipment, a relay forcontrolling: said equipment individual to said switch. a control circuitfor said relay. sa d circuit iimler the control of both of saidari-tions. releaseI equipment for said automate switch, and a releasecircuit for said switih, said supervisory equipment controlled oi' irsaid release circuit.

5T. l'ii a telephone. system, means Jfor establishing a circuitconnection between two points, said circuit connection divided intonormally detached circuit sections, an automatic siiiteh for Closing oneof said .sections witl another, supervisory equipment, a relalr forcontrolling said equip nient individual to said switch, a controlcircuit Jf'or said relay, said control circuit under the cintrol of saidlast; mentioned section l'or rinderiuir it inoperative. releaseequipment l'tr said automatic switch. and a release circuit for saidswitch. said supervisory eqiipnient controlled over said release circili1.

V58. In a 'Telephone system. means for establishing a circuit connectionbetween tivo points. .said circuit connection divided into normallydetached conductor sections. an automatic switch for closingr one otsaid sections with another. a supervisory equipment, a circ'iit foroperating said equipment. .a magnet controlled over said last mentionedse "tion, said supervisory equipment circuit mder the control of saidmagnet whereby t' the last mentioned section is in normal c mdition whenthe automatic switch operates said magnet is operated to control thesupervisoiy equipment to prevent its operation relea'se equipment forsaid automat c switcbaand a release circuit for said switch, saidsiq'iervisory equipment controlled ov Ir said release circuit.

59. In a elephone system, means for establishing a circuit connectionbetween ytwo points. .said circuit connection divided t 1 i l seidmagnet leaves the supervisory equipment free to operate, and' means foroperating the same, release equipment for said automat-ic switch, and arelease circuit for 5 said switch, said supervisory equipment controlledover said release circuit.

60. In a telephone system, a calling line, a called line. means forestablishing a circuit connection between the two, said means dividedinto normally detached circuit sec'- tions. an automatic switch for'closing one of said sections with another, means for operating saidswitch, a supervisory circuit associated with said first mentionedsection, a signal in said circuit and automatic means for operating saidsignal when the said last mentioned section is out of normalworking'condition when said switch is operated. release equipn'ient torsaid automatic switch, and a release circuit for said switch, saidsul'iervisory equipment controlled over said release circuit.

G1. ln a telephone system, a calling line, a calledline, a link circuit.for establishingr a connection with the called line, an automati lswitch for extending the connection from the link to the circuit beyond.means for operating,lr said switch.l a supervisory eir cuit associatedwith Said link. automatic means for connecting said link to saidsupervisory circuit if the circuit beyond is defectivwat theI time theswitch is operated, release equipment for said automatic switch, and .irelease circuit for said switch. said supervisory circuit controlledover said release circuit.

62, ln a telephone system, means forestablishng a talking: circuitconnection between two points. said circuit connection divided intonormally detached sections, an automatic switch t'or extending atalkingr circuit from one ol said sections to another,electromaenelically controlled supervisory mechanism associated withsaid switch. a circuit i'or said mechanism. means for opi 'ativelyenergizing said circuit for operating said mechanism it' the automatic.switch linds the talking). circuit ot one ot' the sections open. meansfor rendering the circuit olA said iinechanism inoperative'it the switchfinds the talking circuit of one ol the sectionsl closed. release.equipment lor said automatic switch. andai release circuit i'or saidswitch. said supervisory mechanism controlled over said release circuit.

uit. ln a telephone system. means for es* tablishing lr a circuiticonnection between two points. said circuit connection divided intol-uormally detached circuit sections. au auto` cui matic switch l'orclosing one ot' said sections i with another. supervisory equipment. aconlIrol circuit. for said equipment. said control :circuit under thccontrol ol' said last luentioned section. release equipment for saidif', automatic switch, and a release. circuit for said switch, said suervisory equipment controlled over said re ease circuit.

64. In a telephone system, means for establishing a. circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an automatic switch for closingr one of saidsections with another, supervisory equipment rindividual to saidswitclua control circuit for said equipment, said control circuit underthe control of said last mentioned section, and a busy test circuit forsaid switch, said supervisory equipment controlled over said busy testcircuit.

(if. In a telephone system. means for establishing a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections. an alitomatic switch forclosing one of saidsections with anotlier, supervisory equipment individual to said switch,a control circuit for said equipment, an auxiliary relay in said lastmentioned section for controlling said control circuit, and a busy testcircuitfor said switch. saidsupervisor)r equipment controlled over saidbusy test circuit.

(i6. in a telephone system. Vmeans for establishilugr a circuitconnection between two points. said circuit connection divided intonormally detached circuit sections. an automatic switch for closing oneof said sections with another. supervisory equipment individual to saidswitch. a control circu'rt for said equipment. an auxiliary relayindividual to said last mentioned section for controlling said controlcircuit. and a busy test circuit for said switch, said supervisoryequipment controlled over said busy test circuit.

(ST. Tn a telephone system. means for tablishinf; a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections. an autolnatic switch for closing.r one ofsaid sections with another. sulwrvisory equipment individual to saidswitch. a control circuit for said equipment. an auxiliary relay in saidlast mentioned section for controlling said control circuit. and acircuit for said auxiliary relay` controlled over said first men-'tioned section. und a busy test circuit for said switch. saidsupervisory equipment controlled over said busy test circuit.

HH. ln a telephone systennineans for establishinz;r a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections/an automatic switch for closing one of saidsections with another. supervisory equipment indi vidnal to said switch.a control circuit for said equipment. said circuit under the control olboth ol said sections. and-a busy test circuit l`or said switch. saidsupervisory equipment controlled over said busy test circuit.

(if). In aftelephone system. means for es tablishing a circuitconnection between two points,y said eirizuit; eonneirtion divided intonormally detached circuit sections. an automatic switch for closing oneof said sections with another. supervisory equipment individual to saidswitch. a eoutrol eireuit. for said equipment. said eouirol ereut underthe control of said last mentioned seetion for rendering it inoperative.and a busy test circuit t'or said switeh. said supervisory equipment(,'ontrolled over said busy test eircuit. i

T0. ln a telephone system. means for es tablishingr a circ-uiteonneetion between two points. said eireuit eonneeliou divided intonormally detaehed eireuit seetions. an autoinatie switeh l'or elosingone of said sei-tions with another. supervisory equipment individual tosaid switrh. and a snpervisonv relay for eont|'ollin; said equipment.said relay` under the eoulrol oll said last mentioned sei-tion. and abusy lest eireuit l'or said switeh. said supervisory equipment eontrolled over said busy test eirruit.

Tl. ln a telephone system. means for establishing a eireuil eonueetionbetween two points. said elreuil eonneetion divided into normallyi'tetarhed eireuit sel-lions. an alltoumtie switeh for elosiutl' one otsaid seetions with another. supervisory equipment individual to" saidswiteh. a supervisory relay for eontrolling said equii'nuent. auauxiliary relay in said last mentioned seetion tor eontrolling saidsupervisory relay. and a busy test eircuit toi` said switch. saidsupervisory equipment controlled over said busy test circuit..

72. ln a telephone system. means l'or establishing rireuit eonneetionbetween two points. said eireuit, eonneetion divided into normallydetaehed eireuit seetions. au automatie switeh for closing one of saidseelious with another. su|wrvisory equipment individual to said switeh.a siqnrvisory relay 'For eoutrolling said equipment. an auxiliary relayindividual to said last mentioned seetion I'or eoutrolling saidsularvisoev relay. and a busy test. eireuit for said switeh. saidslqwrvisory equipment controlled over said busy test circuit,

7?. ln a telephone system. means for establishingr a eireuit.'eonneetion between two points. said eireuit eonneetion divided intonormally detaehed eireuit sections. au alitomatie switeh l'or elosingone ot' said seetions with another. sulwrvisory equipment individual tosaid switeh. a slq ervisory relay I'or eontrolliuer saidV equipment. anauxiliary relay in said last. mentioned seetion for eonlrolliug: saidsupervisory relay. a ereuit for said auxiliary relay eontrolled oversaid lirstLmeutioned seetion. and a busy test eireuitl'or said switeh.said supervisory equipment eontrolled over 'said busy test. eireuit.

Tl. ln a telephone system, means` for es;1J tablishing a circuit.eonuection between two points,sail cir( uit eonnection divided intonorn'ially detaeli ed circuit sections. an automatic switch 'l"o|closing' one of said sections with another. sipervisory equipment individual to said sv iteh. a supervisory relay for eontrolling saidequipment. said relay under the eontrol of both ot' said sections. and abusy test eireuit for said switeh. said supervisory equipn'lenteoutrolled over said busy test (tirellit.

T5. lu a telephone system. means for e5'- tablishing a eiruit eonueetionbetween two points. saidaireuit eonneetion divided into normallydetaeled circuit sei-tions. au auto'- mal ie switeh to l\'elosinf Y oneot said seetions with another. fupervisory equipment individual to saidswiteli. a supervisory relay l'or egmtrollingll said equipment. saidrelay under the eontrol of said last mentioned sei-tion for rendering itinoperative. and a busy test eireuiy for said switch. said supervisoryequipme it eontrolled over said busy test eireuit.

7G. lu a tele )hone system. means tor establishiug' a eileuit eonnertioubetween two points. said eilruit eonneetion divided into normally detaeled eirenit seetions. au automatie switeh t relosiug1one ot' saidseetions with another. aipervisory equipment indi vidual to said sw'itrll. a sulwrvisory relay for eontrolling `sail equipment. said relayun der the eoutro ot' said last mentioned seetion for preventing theaetuation of said supervisory equipment. and a busy test eir enit forsaid switeh. said supervisory equipment eontrollei over said busy testcircuit.

TT. ln a teh phone system. means for establisbing a ei :'cuiteon-neetion between two points. said ei enit eonnection divided intonormally detalhed eireuit sections. an auto malie switeh for elosing oneof said seetions with another. supervisory equipment individual to saidswiteh. a supervisory relay tor eontrolliug.l said equipment. anauxiliary relay in said l: st mentioned section for eontrolling said sipervisoiy relay for preventing.| the aetuation ot' said supervisoryequipment. and a bi sy test eireuit for said switeh. said supervisoryequipment controlled over said busy test :ii-cuit.

7S. ln a tel lphone system. means for establishing a ereuit eonueetionbetween two points. said efreuit eonneetion divided into normally deta'hed eireuit seetions. an alitomatie switch tor elosing one ot saidsections with another. supervisory equipment indi vidual to said.u\'itel1.a supervisory rela)` for eoutrollintr sa d equipment` anauxiliary relay individual to said last mentioned seetion foreoutrolling.r said supervisory relay for preventing: the actuation ofsaid supervisiafy equipment. ai d a busy test eiremt tor said switeb.said supervisory equipment eontrolled over s: id busy test eireuit.

T0. lll a te ephone. system. means lor es .555 vidual to said switch.

tablishing a circuit connectionbetween two points. said circuitconnection divided into normally detached circuit sections, an automaticswitch for closing one of said sections with another, slmervisoryequil'nnent individual to said switch. a supervisory relay Jforcontrolling said equipment, an auxiliary relayr iiuliv-idual to saidlast meu* tioned section for ctmtrolling` said supervisory relay, acircuit for said auxiliary re lay controlled.oveiusaid tirst mentionedsecs tion ior preventin;4 )r the actuation of said supervisoryequipment. and a busy test circuit for said switch, said supervisoryequipment controlled over said busy test circuit.

HU. ln a telephone system, means for es- -tablisliing a circuitconnection between two points. said circuit connection divided intonormally detached circuit sections. an untomat-ic switch for closing oneof said sections with another. Slq'iery-'isorv equipment individualtosaid switch. a si'l'pcrvisory relay tor controllin;r said equil'iment.said relay vinder the control of both of said sections i'or preventing'the actuation ot said super visory equipment. and a busy test circuitfor said switch. said supervisorv equipment con-A trolled over lsaidbusy testcircuit. l

Si. In a telephone system, means for establishirncl a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections. an antoimatic switch, for closing one of saidsections with anotjer'. supervisory equipment indifor controlling saidequipment. said relay under the control of said last n'ientioned sectionfor rendering it inoperative for preventingg the actuation of saidsupervisory 40 equipment. and a busy test circuit for said switch. saidsupervisory equipment eontrolled over said busy test circuit.

Tn a telephone system, means for establishing a circuit connectionhet-wee'n two points. said circuit connection divided into norniallvdetached circuit sections. an anto matic. switch for closingr one of.said sections' with another, supervisory equipment. a relay Forcontrolling said equipment individual to' said switch. a' controlcircuit for said relay. said control vcircuit under the control ot saidlast mentioned section. and a busy test circuit for said switch. saidsupervisory equipment controlled over said busy test circuit.

8?.. Tn a telephone system. means for cstablishiu; r a circuitconnection between two points. said circuit connection divided intonormally detached circuit sections. an alitomatic switch for closing'one of said sections with another. supervisory equipment. a. relav forcontrolling' said equipment individual to said switch. a control circuitfor su id relay. an auxiliary relay in said last mentioned section forcontrolling said control a supervisory relay' circuit, and a busy testcircuit for said switch, said su|jieryisory equipment' controlled oversaid busy test circuit.

Si. In a telephone system, means for establislling` a circuit connectionbetween two points, said circuit connection divided into normallydetached circuit sections, an automatic switch for closing one ot' saidsections with another, sulwrvisory equipment. a relay for controllingIsaid equipment individual to said switch. a control circuit for saidrelay, an auxiliaryv relay individual to said last mentioned section torcontrolling Said control circuit. and a busy test circuit for saidswitch. said slqnrrvisory equipment con- 30 trolled over said busy testcircuit.

S5. Tn a telephone system. means for cstablishing a circuit connectionbetween two points. said circuit connection divided into normallydetached circuit sections, an auto- 35 matic switch for closing one ot'said sections with another. supervisory equipment, a relay't'orcontrolling said equipment individual to said switch. a control circuitfor said relay. an auxiliary relay individual to lsaid last mentionedsection for controllingr said control circuit. a circuit for raidauxiliary relay controlled over said first mentioned section. and a busytest circuit for said switch. said supervisory equipment controlled oversaid busy test circuit'.

96. Tn a telephone system, means tor establishing; a circuit connectionbetween two points. said circuit connection divided into normallydetached lcircuit sections. an alitomatic switch for closing;I one ofsaid sections with another, superv-'isory equipment. a relay forcontrolling said equipment individual to said switch.. a control circuitfor said relay. said: circuit under the control of both of saidsections` and a busy test circuit for said switch. said supervisoryequipment controlled over said busy test circuit.

87. Tn a telephone system. means for establishing n circuit connectionbetween two points. said circuit connection divided into n allyikitnchcd circuit sections. an automatic switch for closingr one of saidsections with a'nother. supervisory equipment. a relay fmcontrollincrsaid equipment individual to said switch. a cont-rol circuit for saidrelay. said control circuit under the control of said last mentionedscctionfor renderingr it inoperative. and a busy test circuit for saidswitch, said supervisory equipment controlled over said busy testcircuit.

8S. Tn a telephone system. means for establishing a circuit connectionbetween two points. said circuit connection 'divided into normallydetached conductor sections. an automatic switch` for closing one ofsaid scctilens with another.I a supervisory equipment. a circuit foroperating said super-A visorv equipment, a magnet controlled over saidlast mentioned section, said supervisory 13o equipment circuit under thecontrol of said magnet whereby if the last mentioned scction is innormal condition when the automatic switch operates said magnet isoperated to control the supervisory equipment to preventits operation1and a busy test circuit for said switch, said supervisory equip mentcontrolled over said busy test-circuit.

89'. In a telephone system, means for es tablishingr a circuitconnection between two points, said circuit connection divided intonormally detached conductor sections, an

automatic switch for closing one ot said sect-ions with another, asupervisory equipment, a circuit for operating;r said equip.- ment, amagnet controlled over said last mentioned section, said supervisoryequipment circuit under the control of said magnet whereby if the lastmentioned section is in normal condition when the automatic switchoperates said magnet is operated to control the supervisory equipment toprevent its operation, and whereby if the said last mentioned section isnot in normal' condition, when the automatic switch operates, saidmagnet leaves the supervisory equipment free to operate, means foroperating the same, and a busy test circuit for said switch, saidsupervisory equipment controlled over said busy tcst circuit.

9U. In a 'telcphonc system, a calling,r line, a called line, means forestablishing a circuit connection between the' two, said means dividedinto normally detached circuit sections, anautomatic switch for closingone of said sections with another, means for operating said switch, asupervisory circuitassociated with said first mentioned section, asignal in said circuit and automaticrmcans for operating said signalwhen the said last mentioned section is out of normal working.,lrcondition when said switchis olwratcdgaml a busy test circuit Jor saidswitch, said supervisory circuit controlled over said busy test circuit.

91. In a telephone system, a calling line, a called line, a link circuitfor establishing a connection witlr the called line, an automatic switchfor extending the connection one of said sectinns to another,electromagnetically controlled Isupervisory mechanism associated withsaid switch, said mechanism, means for operatively energizing saidrircuit for operatingr said 'mechanism if thi automatic switch finds thetalking circ-uit (f one of the sections open, and means for renderingthe circuit of said mechanism inoperative if the switch finds thetalkingr cir( uit of one of the sectionsclosed, and a ousy test circuitfor said switch, said supervisory mechanism controlled over sait, busytest circuit.

93. In a teler hone system, means for establishing a circuit connectionbetween two points. said circuit connection divided into normally detacled circuit sections, an automatic `switch for closing one of saidsections with another, supervisory equipment, a control circu t for saidequipment, said control. circuit i nder the control of said lastmentioned section, and a busy test circuit for said switch. saidsupervisory 'equipment controlled over said busy test circuit.

Signed by` us at Chicago, Illinois, this 20th day of November, 1913.

GEORGE A. YANOCHOIVSKI. 'HARRY I". HERSHEY. W itnesscs lgI. W. Ilmnmi,Amon (law/uio.

a circuit for

